Patents by Inventor Toshiharu Shirakura

Toshiharu Shirakura has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5202898
    Abstract: The present invention relates to a laser oscillator, especially to a laser oscillator suitable for ultrafine manufacturing such as an apparatus for manufacturing of a semiconductor wherein the laser oscillator is provided with constant directivity chronically, although the directivity is not so fine, for avoiding a blurred image spatially and chronically in order to obtain a stable mask in the ultrafine manufacturing.
    Type: Grant
    Filed: July 22, 1991
    Date of Patent: April 13, 1993
    Assignees: Hitachi, Ltd., Hitachi Engineering Co., Ltd.
    Inventors: Hiroyuki Sugawara, Toshiharu Shirakura, Takeshi Yamamura, Hideki Yamai
  • Patent number: 5117434
    Abstract: A metal vapor laser has a discharge tube with electrodes at opposite ends. A power source is electronically connected to the electrodes and generates a discharge in a discharge region within the discharge tube. The discharge generates laser light which emerges from the tube via windows. In order to cool the apparatus, the discharge tube is surrounded by a cooling jacket in the form of a hollow cooling vessel. A liquid flows in the cooling vessel and removes heat. The space between the cooling vessel and the discharge tube is evacuated. The cooling vessel is conductive and, since it is connected between one of the electrodes and the power supply, its inner and outer walls provide two potential paths for return current. The fact that the inner and outer walls have different diameters means that the inductance of the return paths is large. Therefore, the outer wall has a gap in it filled with insulating material.
    Type: Grant
    Filed: January 15, 1991
    Date of Patent: May 26, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Tuneyoshi Oohashi, Motoo Yamaguchi, Akira Wada, Toshiharu Shirakura, Toshimichi Kichikawa, Hiroyuki Sugawara
  • Patent number: 4991180
    Abstract: A metallic vapor laser apparatus includes a cylindrical discharge tube (31) having an internal space (2), a heat-insulating material (6) encompassing the periphery of the discharge tube (31), and two electrodes (3a) and (3b) having a cylindrical portion coaxial with the discharge tube (31) and disposed at both ends of the discharge tube (31). The internal space (2) are filled with a gas containing the vapor of copper as a laser medium for effecting laser oscillation by the excitation of the filler gas and the discharge.
    Type: Grant
    Filed: May 18, 1990
    Date of Patent: February 5, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Motoo Yamaguchi, Hiroyuki Sugawara, Akira Wada, Toshiharu Shirakura, Tuneyoshi Oohashi, Toshimichi Kichikawa
  • Patent number: 4740980
    Abstract: In a gas laser device according to this invention, a gas inlet having an electrode protrudes within each of expanded portions protruding on the side, where the gas inlet is disposed, of the principal portion of the discharge tube. Gas medium ejected from the gas inlet in the principal portion of a discharge tube collides with the inner surface of the principal portion of a discharge tube, while forming a flame extending along the ejected gas medium from the electrode and is divided into two partial flows. One of them flows along the wall of the expanded portion; collides with the gas inlet; and is divided further into two partial flows. Therefore it does not collide with the gas medium within the gas inlet. Consequently the gas medium and the flame fluctuate hardly and are stabilized. In this way it is possible to stabilize the laser output.
    Type: Grant
    Filed: October 16, 1986
    Date of Patent: April 26, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Toshiharu Shirakura, Hiroyuki Sugawara, Shigeo Shiono, Minoru Suzuki, Humio Shibata
  • Patent number: 4602372
    Abstract: A discharge tube structure of a gas laser generator has end common vessels at its both end sections and an intermediate common vessel at its intermediate section. The end common vessels and intermediate common vessel are connected through the first and second cooling ducts to a centrifugal blower, which is provided at its center the first communicating port communicating with the first cooling duct and at least two second communicating ports communicating with the second cooling ducts opposed to each other with respect to the first communicating port. The simplified second cooling ducts allows the mixture gas to be supplied smoothly to the intermediate common vessel, thereby increasing the laser output.
    Type: Grant
    Filed: November 8, 1983
    Date of Patent: July 22, 1986
    Assignee: Hitachi, Ltd.
    Inventors: Kouji Sasaki, Hiroyuki Sugawara, Kouji Kuwabara, Toshiharu Shirakura, Yukio Kawakubo, Satoshi Takemori
  • Patent number: 4590599
    Abstract: A gas laser device has an anode and a cathode arranged oppositely in a discharge tube. The cathode comprises a plurality of cathode members each having a predetermined discharge effective cathode surface and each being electrically isolated from others. A switching circuit selects the cathode member(s) used for a continuous wave oscillation and the cathode member(s) used for a pulsed oscillation. The total area of the discharge effective cathode surface(s) of the cathode member(s) used for the pulsed oscillation is selected to be smaller than, preferably 1/3 to 1/2 of that of the discharge effective cathode surface(s) of the cathode member(s) used for the continuous wave oscillation.
    Type: Grant
    Filed: May 31, 1983
    Date of Patent: May 20, 1986
    Assignee: Hitachi, Ltd.
    Inventors: Yukio Kawakubo, Hiroyuki Sugawara, Kouji Kuwabara, Toshiharu Shirakura, Satoshi Takemori, Kouji Sasaki
  • Patent number: 4541097
    Abstract: A gas laser has an electrode of improved construction. The electrode, for example a cathode, comprises an inner cathode and at least an outer cathode spaced from the inner cathode and disposed on the side thereof away from to an anode. Each of the cathodes has a central hole from which glow discharge is formed, and the outer cathode further has a plurality of through-holes around the central hole. A gas medium flowing in a discharge tube passes through the central hole of the inner cathode via the central hole and through-holes of the outer cathode. The gas medium forcedly enters the glow discharge from the inner cathode thereby to cause it expand and a part of the gas medium having passed through the through-holes of the outer cathode squeeze the glow discharge from the outer cathode so that the glow discharge can enter the glow discharge from the inner cathode. Therefore, the current density of the glow discharge in the discharge tube is made information.
    Type: Grant
    Filed: November 24, 1982
    Date of Patent: September 10, 1985
    Assignee: Hitachi, Ltd.
    Inventors: Kouji Kuwabara, Kouji Sasaki, Hiroyuki Sugawara, Toshiharu Shirakura, Yukio Kawakubo, Satoshi Takemori
  • Patent number: 4500998
    Abstract: The invention is to provide a gas laser in which a discharge tube of a double-tube construction comprising a inner tube and an outer tube of a relatively large diameter is employed, a tubular discharge space filled with a gas mixture is formed between the inner tube and the outer tube, a gas mixture cooling passage is formed within the discharge space, and a pair of mirror groups are disposed at both ends of the discharge space, each mirror group comprising a plurality of mirrors arranged in the circumferential direction. The respective mirrors are arranged in such a manner that a laser beam is reflected by the mirrors to go and return in the discharge space several times and each path of the laser beam between the corresponding two mirrors obliquely intersects the central axis of the discharge space.
    Type: Grant
    Filed: August 24, 1982
    Date of Patent: February 19, 1985
    Assignee: Hitachi, Ltd.
    Inventors: Kouji Kuwabara, Hiroyuki Sugawara, Toshiharu Shirakura, Yukio Kawakubo, Kouji Sasaki
  • Patent number: 4474468
    Abstract: According to the invention, a thin wire 13 is arranged across the laser beam 2, and the change of resistance in the thin wire 13 is measured by a resistance meter 21 while moving the thin wire 13 by a driving mechanism 23, thereby to measure the power of the laser beam or the position of the laser beam. The apparatus can be used for monitoring the power of laser beam or position of the same used in the high-power laser device for processing or the like purpose. According to the invention, it is possible to monitor the power and position of the laser without interrupting the laser beam and without incurring substantial increase of the loss of power of the laser beam.
    Type: Grant
    Filed: September 9, 1981
    Date of Patent: October 2, 1984
    Assignee: Hitachi, Ltd.
    Inventors: Toshiharu Shirakura, Hiroyuki Sugawara, Kouji Kuwabara, Kouji Sasaki, Satoshi Takemori
  • Patent number: 4468777
    Abstract: A gas laser oscillation apparatus wherein, in order to prevent a center axis of a reflecting mirror included in a laser resonator from deviating from an optical axis of the laser resonator due to the deformation of a mirror supporting frame caused by a vacuum force applied to a laser tube, the reflecting mirror is fixed to a mirror holding plate, which is attached to the mirror supporting frame with fasteners such as bolts and nuts.
    Type: Grant
    Filed: October 2, 1981
    Date of Patent: August 28, 1984
    Assignee: Hitachi, Ltd.
    Inventors: Satoshi Takemori, Hiroyuki Sugawara, Kouji Kuwabara, Toshiharu Shirakura, Yukio Kawakubo, Kouji Sasaki
  • Patent number: 4391519
    Abstract: A laser beam axis monitoring apparatus which includes a laser oscillator generating a laser beam and a light generator for generating a light for monitoring an axis of the laser. The light from the light generator is split into ring-shaped light and reflected or lead into the laser oscillator. The light in the laser oscillator is reflected by a total reflection mirror and passes out of the oscillator so that the axis of the laser beam and axis of the light coincide with each other.
    Type: Grant
    Filed: September 12, 1980
    Date of Patent: July 5, 1983
    Assignee: Hitachi, Ltd.
    Inventors: Kouji Kuwabara, Hiroyuki Sugawara, Toshiharu Shirakura, Kouji Sasaki, Satoshi Takemori
  • Patent number: 4351052
    Abstract: In a coaxial type gas-flow laser device in which a laser beam axis, an electric discharge axis and a gas flow axis are coincident, at least one centrifugal blower is employed for circulating a laser gas. Where two centrifugal blowers are employed, they oppose to each other in an axial direction of discharge tubes.
    Type: Grant
    Filed: February 7, 1980
    Date of Patent: September 21, 1982
    Assignee: Hitachi, Ltd.
    Inventors: Kouji Sasaki, Hiroyuki Sugawara, Kouji Kuwabara, Toshiharu Shirakura, Satoshi Takemori, Norio Ikemoto
  • Patent number: 4331939
    Abstract: An invention concerning the electrode structure of a gas laser device is disclosed. In the outer peripheral part of a discharge gas circulating hole (32) provided in the central part of an upper gas stream side one (16) of electrodes (14) and (16) disposed at both the ends of a discharge tube (8), a plurality of gas circulating apertures (34) are further provided over the entire periphery. A glow discharge portion in the discharge tube (8) is fined towards the central part of the tube by a gas which passes through the outer-peripheral gas circulating apertures (34). Thus, the laser intensity profile becomes the Gaussian distribution, and the laser generation efficiency is enhanced.
    Type: Grant
    Filed: February 6, 1980
    Date of Patent: May 25, 1982
    Assignee: Hitachi, Ltd.
    Inventors: Kouji Kuwabara, Hiroyuki Sugawara, Toshiharu Shirakura, Kouji Sasaki, Satoshi Takemori
  • Patent number: 4287487
    Abstract: A gas laser generating device of the longitudinal gas flow type having at least two glow discharge tubes, each of which has positive and negative electrodes, electric insulating tubes which are inserted between the two glow discharge tubes in order to provide insulation therebetween, and mirrors which are positioned at the ends of the two glow discharge tubes. In the glow discharge tubes, gas is excited to generate gas lasing and this gas lasing is amplified by the reflections of the mirros. Also, there are further provided triggering electrodes near either the negative or positive electrodes of the glow discharge tubes, respectively, which triggering electrodes are connected to the positive electrodes through triggering resistors, respectively.
    Type: Grant
    Filed: June 26, 1979
    Date of Patent: September 1, 1981
    Assignee: Hitachi, Ltd.
    Inventors: Kouji Kuwabara, Hiroyuki Sugawara, Toshiharu Shirakura, Kouji Sasaki, Satoshi Takemori